One of the officers who helped subdue an alleged pot smoker two weeks ago in a Brooklyn subway station has come forward with a detailed account that helps support the man’s claim that police sodomized him with an object during a vicious attack, law-enforcement sources said yesterday.

The officer, who works for the NYPD’s Transit Bureau, has told his story to his union delegate and an attorney, an account that was then provided to the Brooklyn District Attorney’s Office and the NYPD’s Internal Affairs Bureau.

The transit cop said he was one of the officers trying to subdue tattoo-parlor worker Michael Mineo. He said that while he was holding Mineo down, trying to handcuff him, he saw one of the officers “jab” him in the buttocks with an object, sources said.

The transit officer couldn’t be certain whether another officer actually penetrated Mineo or simply hit him on the outside of his buttocks, said the sources, who declined to identify the object the cop said was used.

The DA’s office is still awaiting tests on a radio and baton belonging to Alex Cruz, one of the cops allegedly involved in the incident.

Cops are often reluctant to provide evidence against other officers, and the transit officer’s account could prove stunning and damning.

The cop’s version of events gives added impetus to an investigation by the DA and IAB.

“It’s a major development,” a law-enforcement source said.

A special grand jury was empanelled earlier this week to examine Mineo’s allegations.

The officer has yet to speak directly to either the DA or the NYPD, and it’s unknown when he’ll go before the grand jury, sources said.

But a source said, “He knows what happened. He saw what happened.”

Another source said his account is “detailed” and supportive of Mineo’s story.

The transit officer joined four cops who chased Mineo into the Prospect Park B/Q subway station on Oct. 15 after seeing him smoking a joint on the street.

He was one of four cops who grappled with Mineo, who was then allegedly sodomized with an object. A fifth cop was there but wasn’t involved in the struggle.

Sources say that witness accounts, internal injuries and an approximately half-inch-by half-inch tear in Mineo’s underwear supported his allegations.

Since the story broke a week ago, the NYPD has maintained that none of the witnesses saw Mineo being sodomized.

The officers were even kept on full, active duty.

But they were eventually placed on desk duty – not because of the allegations, but to protect them from media scrutiny, the department said.

For the past three days, the DA has called witnesses before the grand jury.

Mineo’s lawyer, Kevin Mosely, said there are as many as 18 witnesses and that evidence against the cops is “overwhelming.”

Sources say at least two witnesses will say they heard Mineo yell to the cops, “What are you doing to me!” and then to one officer, “What are you . . . a faggot?”

Mineo met with officials from the DA’s office for an hour yesterday, but collapsed in pain and had to end the meeting, his lawyers said. Mosely expects Mineo to testify before the grand jury next week.